Charge-Regulated Reduction Potential of Phenazine Enabling Electrochemiluminescence for Monitoring Riboflavin in Beans Germination

Nowadays, organic molecules with excellent fluorescence often lack electrochemiluminescence (ECL), which seriously restricts their analytical and biomedical applications. In this work, we functionalized phenazine (PZ) derivatives by with the charged moieties and activated their ECL properties using K 2 S 2 O 8 as a coreactant, achieving a significant “off-to-on” ECL emission transition. For that, 7,8-dihydroxyphenazine-2-carboxylic acid (DHPZ) was synthetized, showing the largest ECL efficiency of 56.4% (versus Ru(bpy) 3 2+ as a standard). Its subsequent self-assembly with ethylene glycol (termed as DHPZ-EG) as emitter further boosted the 4.0-fold ECL efficiency. In the presence of riboflavin (RF), the DHPZ-EG assemblies underwent the light-induced photocatalytic oxidation (PR), enabling efficient ECL signal transduction via the structure-property correlation. The as-established ECL sensor exhibited a wide linear section from 10 nM to 1.0 mM and a limit of detection (LOD, 1.5 nM), and the ability to monitor the broad bean growth metabolism. This work opens a novel avenue for designing organic luminophores and developing sensors for dynamic botanical tracking.